A measure of telecommunications traffic density. The unit call is a dimensionless "unit" representing a traffic density of 10 call-seconds per hour, or 1/3 erlang
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}